I could write an entire article about this (possibly someday I will), but to explain it briefly: I feel it hurts my creative process to have to take the time to write these commit messages at every commit. It's making me not want to commit. I treat a commit as an extended save operation, so unconsciously avoiding saving is definitely not something you want to do. I know most people would object to my use of a commit as an extended save, but I stand by that opinion as well, especially in these days of deploy-by-commit systems like Heroku. Sometimes I make commits that are smaller than a commit message would be so having to write a message will be a big waste.

Also, commit messages are a form of documentation; but they are one of the least useful ones. Much less useful in my opinion than docstrings, topical guides, references and blog posts. So I think that spending time on them is a much lower priority than spending time on the other kinds of documentation.